The <mx:ProjectBar> tag has a source attribute. I have
created a custom MXML component that has a source attribute, but I
want it to accept only a specific object type. Right now I have it
set to to receive a generic Object type. If I change it to a custom
object type, example MyCustomType:

public var myCustomASClass:MyCustomType;

<myforms:MyCustomMXMLComponent
source="myCustomASClass"/>

FlexBuilder shows this error:

Initializer for 'source': values of type MyCustomType cannot
be represented in text.

The application compiles, but Flex Builder continues to show
an error.

Is it possible to pass a typed instance of an AS class to a
custom MXML component?